This is a scheduled Ubuntu 20.04 retirement. Ubuntu 20.04 LTS runner will be removed on 2025-04-15. For more details, see https://github.com/actions/runner-images/issues/11101
Currently phpBB tests suite runs SQLite and MSSQL tests on ubuntu-20.04 image.
phpBB tests configuration should be updated to move mentioned tests to ubuntu-22.04 or later.